IF you mean "can we see other aircraft on radar with any reasonable hope of avoiding them, or even finding them" the answer is "NO".
The occasional aircraft will place a return on weather radar - but as the beam only sweeps horizontally at a fairly narrow altitude range, it is a very hit or miss (and very much mostly miss) to see an aircraft return on weather radar.
There is a Traffic Collision avoidance system which uses a radio beacon on each aircraft (obviously this can be turned off in times of war!) to show (and thus avoid) traffic.